How we cite our quotes: All quotations are from Star Wars: A New Hope.
Quote #1
OLD MAN: Hello, there. Come here, my little friend. Don't be afraid.
R2: Bleep, wooo.
OLD MAN: Oh, don't worry. He'll be all right. (Luke awakens.) Rest easy, son. You've had a busy day. You're fortunate to be all in one piece.
LUKE: Ben? Ben Kenobi? Boy, am I glad to see you.
BEN: The Jundland Wastes are not to be traveled lightly. Tell me, young Luke, what brings you out this far?
Luke lacks the power to survive in the world on his own. One Sand Person puts him out for the count. Thankfully, old Obi-Wan's got his back.
Quote #2
LUKE: The Force?
OBI-WAN: The Force is what gives a Jedi his power. It's an energy field created by all living things. It surrounds us, penetrates us, it binds the galaxy together.
The Force is the source of power for both Obi-Wan and Darth Vader. Both men are able to tap its energy, but despite having a mutual source, they use that power for very different means.
Quote #3
IMPERIAL OFFICER: Don't try to frighten us with your sorcerer's ways, Lord Vader. Your sad devotion to that ancient religion has not helped you conjure up the stolen data tapes or given you clairvoyance enough to find the rebels' hidden fortre—
DARTH VADER: I find your lack of faith disturbing.
TARKIN: Enough of this. Vader, release him.
Darth Vader uses the Dark Side of the Force. He exerts its power in a violent manner to get what he wants. In this case, he wants everyone to know they don't troll his religion.